[ 2 74 ] 
fome have hexagonal Sheaths defcribed one within 
another, as in Fig. 17. Tab. V. In the firfl Cafe, the 
fhottenjuice was of one and the fame Nature and Con- 
fiftency, equally impregnated, and the Produdion of 
one Effort; in the latter Cafe, where the Sheaths are 
one within another, 'tis alfo the Product of one Effort 
or Shoot, the Concretion of one and the fame time, 
as the tremulous Undulations upon the Surface of 
Water, on throwing in a Stone, are ail the Offspring 
of one Force, tho’ the flrd he ftrongeft, and the red 
gradually fainter and lefs diflind : But the juices being 
differently mix'd, gave way to the Effort in proportion 
to their Senfibiiity of the impregnation, the mod agile 
flying off to the greated Didance from the Center, 
and the mod mix'd, coarfed, and mod opaque, re- 
maining neared the Center (24.). That this is he true 
Procefs, and that thofe different Sheaths are the Pro- 
duce of one Effort or Birth, and not formed at dif- 
ferent times, and in Succeflion, as Steno and Aldro- 
‘ vandus , and fome others, fay (2f), is plain, I think, 
from the two following Obfervations (26). If the 
juice which forms thefe Sheaths was impregnated and 
fhot at different times, it would not form in Sheaths 
round what appears to be the Central or Mader-fhoor, 
but would projed itfelf into its natural hexaedral Fi- 
gure. If it were not impregnated, but mere Spar 
only, without Nitre, or any other adive Principle, it 
would form itfelf, as the Staladites, in a pendulous 
undulating Diredion, Drop or Wave upon Wave; 
and in this Cafe thefe Sheaths could never furround, 
in that neat and exad manner, the central Shoot ; 
but 
(24) See TTg. 12. Tab. IV. and its Defcription, p. 263. 
(253 See Plot's Oxf. p. 98. (26) See p. 259. Note (13) 
